Continuity tester



J. R. KADILAK CONTINUITY TESTER Dec. 19, 1950 Filed March 5, 1948 JNVENTOR. Joseph R.' Kad/Yak Patented Dec. 179, A195() omiso :sums PATENT oFF-lcs v32,534,456 'j f-ITY Joseph R. KadilakfMidlandyPa. jmsplicacimmmh 5, 194s, sfiai -rs,"a

This invention relates to continuity testing devices, and more particularly to a combined screw driver and continuity testing apparatus.

A main object of the invention is to provide a novel and improved screw driver device useful especially to those engaged in electrical work, which may also be employed as a continuity tester for electrical circuits, said device being very simple in construction, easy to handle and requiring no external power source.

A further object of the invention is to provide an improved combination screw driver and electrical continuity tester which is inexpensive to manufacture, rugged in construction and very compact in size.

Further objects and advantages of the invention will become apparent from the following description and claim, and from the accompanying drawings, wherein:

Figure 1 is a longitudinal cross-sectional view taken through an improved screw driver device constructed in accordance with the present invention.

Figure 2 is a vertical transverse cross-sectional view taken on line 2-2 of Figure 1.

Referring to the drawings, II designates the metal shank of the screw driver, and I2 designates a hollow clear plastic handle which is rigidly secured to the end of shank II. The cavity inside handle I2 is designated at I3, is generally cylindrical in shape and is axially aligned with shank II. The end of shank II projects into cavity I3 and is formed with a conical tip, as shown at I4.

Threaded into the cavity I3 at the outer end of handle I2 is a' clear plastic plug I5. Moulded axially in plug I5 is a metal insert I6 formed at its outer end portion with a cavity I'I in which is received an end of an insulated iiexible conductor I8. Extending through insert IB is a wire I9 which is connected, as by soldering, in cavity I1 with the wire core of insulated conductor I8. Wire I9 is embedded in the plug I5 and emerges therefrom at the inner end of said plug opposite to cavity I'I, terminating in a metal ring 20. Said inner end is formed with an axial bore 2| which is internally threaded adjacent ring 20 and which receives a flashlight bulb 22, as shown in Figure 1, the shell of the bulb base engaging the ring 20.

Designated at 23 is a ilashlight cell which is positioned in cavity I3 with its end wall in contact with tip I4 and its center terminal post engaging the center contact of the bulb 22.

Connected to the free end of insulated conductor I8 is a metal prod 24. When the shank (Gratta- 1833) I I and prod 24 are placed across a low-resistance continuous circuit, lamp 22 becomes energized and indicates the continuity of said circuit. If the circuit is open the lamp 22 fails to become energized.

The battery 23 may be readily removed for replacement whenever required by unscrewing plug I5 from the cavity I3.

While a specific embodiment of a combination screw driver and electrical continuity tester has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore it is intended that no limitations be placed on the invention except as defined sby the scope of the appended claim.

What is claimed is:

A continuity tester for electrical circuits com prising an elongated transparent tubular handle formed of electrical insulating material and having a cylindrical bore extending throughout substantially its entire length and through one end of the handle, said bore being screw threaded at its end extending through said end or the handle, an elongated metal shank secured to the end of the handle remote from the screw threaded end of the bore and extending longitudinally beyond the handle and having its inner end projecting into the bore of the handle, an elongated transparent screw threaded plug engaging within the screw threaded end of the bore and formed of electrical insulating material and having its outer end substantially flushl with the adjacent end of the handle, the screw threaded plug being provided in its outer end with a central longitudinal elongated recess having its inner end terminating near the longitudinal center oi' the screw threaded plug, an elongated metal insert mounted within said elongated longitudinal recess of the plug and extending for the entire length of such recess and having its outer end disposed substantially ush with the adjacent ends of the plug and handle, the metal insert having a central longitudinal recess in its outer end, an elongated flexible insulated conductor having one end anchored within the recess of the metal insert, the transparent screw threaded plug being provided in its inner end remote from the metal insert with'a central longitudinal screw threaded opening, a light bulb disposed within the screw threaded opening of the plug and including a metallic screw threaded base engaging the screw threads of the plug opening and forming one terminal of the light bulb, the metallic screw threaded base 3 of the light bulb extending longitudinally beyond the inner end of the transparent plug and into the bore of the handle, the light bulb including a second terminal carried by the end of the metallic screw threaded base within the bore of the handle, a flashlight battery mounted within the bore of the handle and having one end contacting said second terminal of the light bulb and its other end contacting the inner end of the shank projecting into the bore of the handle, a conducting ring disposed adjacent to the inner end of the transparent plug and surrounding the metallic screw threaded base of the light bulb and dis-l posed in electrical contact therewith, and a wire connected with the conducting ring and extending longitudinally through the transparent plug and metal insert and embeddedv within the plug and insert and having its end remote from the light bulb leading into the recess of the metal insert and electrically connected wtih said flexible insulated conductor.

JOSEPH R. KADILAK.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS 10 Number Name Date 2,116,448 OBrien et al May 3, 1938 2,156,319 Steele May 2, 1939 2,213,973 Woodring Sept. l0, 1940 2,413,484 Berger Dec. 31, 1946 u Y v FOREIGN PATENTS Number Country Date 259,275 Great Britain Sept. 20, 1926 Great Britain Aug. 18, 1932 

